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Thread ID: 144001 2017-06-02 22:38:00 America's Cup 2017 Greg (193) PC World Chat
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1436135 2017-06-18 09:07:00 Its actually quite simple if you have any knowledge of aerodynamics . If you look at the Boats ( or planes as they almost are) their "sails" are no longer called that. They are all referred to as WINGS. That's because they basically are just that.

Now if you know how an airplane wing works, then its really simple. A wing creates lift due to different air pressure above and below the Wing.
Add in the foils, their shape, less surface drag, size, different designs for low to high wind and you basically have a plane.

If you googled it, there are plenty of explanations on how it works,. Since that action on its own doesn't really seem to sink home here you go :p

bfy.tw Happy reading.

In the case of perfectly still air, no wind at all then of course they cant move. So Can you please post an article where it claims with NO WIND these boats are foiling.

Even the slightest amount of wind is enough to make them move. looking forward to the article with NO WIND.

I really don’t know why I’m bothering to respond given the stupidity being displayed, but I guess if you want to make a right dick of yourself then who an I to stop you.

Firstly, I am not disputing the Aerodynamics of an Aeroplane Wing.

The Wright Brothers were even on to it.

The problem is that in the case in question you need air passing over the wings at sufficient velocity to provide lift.

To enable this to happen you need power to produce the airflow and this is obtained courtesy of a motor turning a propeller or a jet engine dragging the wing forward at sufficient speed for it to obtain lift.

Ok, back to our boat, we don’t have a motor, so we need something else to propel us, and in the case of a yacht, and variations there of, this has traditionally been obtained by a sail.

Now the sail, like a wing, can be adjusted to produce the most power, and it is the job of the trimmer to get the sails the right shape to produce the most power.

All this gets down to airflow over the Sail or the Wing so it follows if there is no Wind there is no Airflow of consequence so you’re going nowhere.

Now you ask: “In the case of perfectly still air, no wind at all then of course they cant move. So Can you please post an article where it claims with NO WIND these boats are foiling.

Well if you had bothered to follow Wal’s link, and noted what the expert said, as I’ve already pointed out, (8 min 40 secs into the video) instead of going off half cocked you will note he claims that these boats can do 24 knots against a 12 knot current without ANY WIND.

That’s the crunch and what interests me.

You also say that: “In the case of perfectly still air, no wind at all then of course they cant move".

Not so by the sound of it, and we have already been told that windsurfers can, so you'd better check with your mates. :lol: 		B.M. (505)
1436136 2017-06-18 10:10:00 I really don’t know why I’m bothering to respond given the stupidity being displayed, but I guess if you want to make a right dick of yourself then who an I to stop you.

Firstly, I am not disputing the Aerodynamics of an Aeroplane Wing.

The Wright Brothers were even on to it.

The problem is that in the case in question you need air passing over the wings at sufficient velocity to provide lift.

To enable this to happen you need power to produce the airflow and this is obtained courtesy of a motor turning a propeller or a jet engine dragging the wing forward at sufficient speed for it to obtain lift.

Ok, back to our boat, we don’t have a motor, so we need something else to propel us, and in the case of a yacht, and variations there of, this has traditionally been obtained by a sail.

Now the sail, like a wing, can be adjusted to produce the most power, and it is the job of the trimmer to get the sails the right shape to produce the most power.

All this gets down to airflow over the Sail or the Wing so it follows if there is no Wind there is no Airflow of consequence so you’re going nowhere.

Now you ask: “In the case of perfectly still air, no wind at all then of course they cant move. So Can you please post an article where it claims with NO WIND these boats are foiling.

Well if you had bothered to follow Wal’s link, and noted what the expert said, as I’ve already pointed out, (8 min 40 secs into the video) instead of going off half cocked you will note he claims that these boats can do 24 knots against a 12 knot current without ANY WIND.

That’s the crunch and what interests me.

You also say that: “In the case of perfectly still air, no wind at all then of course they cant move".

Not so by the sound of it, and we have already been told that windsurfers can, so you'd better check with your mates. :lol:

You can pump the sails to move. 		prefect (6291)
1436137 2017-06-18 10:43:00 BM - Why don't you do your own looking instead of proving with every post what a right troll you really are . Cant you look things up to get an answer ? Referring to the no wind. Its easy to figure out, but must be above your thought / understanding level.

There's ONLY ONE thing you're good at and that's ruining EVERY thread you post in. 		wainuitech (129)
1436138 2017-06-18 21:08:00 Coming back to what BM was asking which is quite valid "How Does One Sail Upstream At Double The 12 Knot Flow In Nil Wind Conditions"

www.sailingscuttlebutt.com

Right my take on it would be as you are drifting down stream you would have a Breeze in your face the same as you have on a Bike on a still day.

Back on the Amazon on the High Tec AC50 with their state of art wing design they would start by going across the current and with the combination of the Foils which to me is key they could Tack at speed and achieve forward speed going upstream(not straight upstream but tacking at speed)

Now coming back to the Foils these also create lift (same as a Aircraft wing) but also have the same effect as the sail adding to the total speed and very little Drag while it is up on the Foils

Just looking at the Foil design of Team NZ to my mind this is way above the others due to it's multi dihedral Design and create Lift (which can be traded for speed) which is now state of art in the world of Soaring with wing design with the use of winglets to maximize L/D (Lift over Drag ratio) which since the 80's which was about 35 L/D to now around 60 L/D

I also wonder if we will see if we will see Tips on the Foils(they can change the Tips) with more upturn like Winglets to cut the vortices's but the foil design may negate these

Many may say Water and Air are not the same but they are both fluid

See the similarity here with the Latest Tech 		Lawrence (2987)
1436139 2017-06-18 21:37:00 Yep, its all to do with those foil design, get it right for the day and its all good. As JS mentioned in the onboard interview, they take 80 Days (think he said) to make new ones, so its not like they can just pull them off the shelf unless you have them sitting there.

I see the help from team Japan is working well for them :) 		wainuitech (129)
1436140 2017-06-19 01:24:00 With surplus hot air from this forum plus a cunningly rigged umbrella a coal barge could tow water-skiers up the Huka Falls. ;)

Yes, but could it do it on an endless treadmill?? 		Richard (739)
1436141 2017-06-19 01:25:00 Oh dear. Please help me no. :p :badpc: wratterus (105)
1436142 2017-06-19 22:39:00 I don't like the 5 day rest period. No doubt Oracle will use it to spend $millions on all manner of fine tuning to improve boat speed.
Unlike Greg I was pleased to the departure from TeamNZ of Dean Barker as (perhaps unfairly) I did not perceive him as having a winner's mind-set.
What is so fascinating about this Cup is the way that each Challenge series brings in so much by way of boats changes.
In this series the boats are so fast and races so short that the smallest error can have a non recoverable adverse effect on the race. 		Neil F (14248)
1436143 2017-06-20 16:00:00 In this series the boats are so fast and races so short that the smallest error can have a non recoverable adverse effect on the race.Yeah, and that's a lousy aspect to the races from a spectator's perspective. Greg (193)
1436144 2017-06-21 01:16:00 LMAO - B.M. (bowel movement) Banned yet again!!

Good job 		bevy121 (117)
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